AA6061 Alloy Research Articles

Precipitation Behavior and Corrosion Properties of Stirred Zone in FSWed AA5083 Al-Mg Alloy after Sensitization

This paper investigated the Mg-rich phase precipitation behavior and the corrosion performance throughout the thickness direction within the stirred zone (SZ) of friction stir welded (FSW) AA5083 alloy after 175 °C/100 h sensitization. For the as-welded SZ, the recrystallized grain size gradually decreased from the top surface (5.5 μm) to the bottom (3.7 μm). The top and bottom of the SZ maintained relatively high levels of deformed grains and accumulated strain induced by either shoulder pressing or pin stirring. After 175 °C/100 h sensitization, 100 nm thick β′-Al3Mg2 precipitates were present along the grain boundaries (GBs) in the SZ. The bottom of the SZ exhibited more continuous precipitates along GBs due to the fine grain size and the large fraction of high-angle grain boundaries (0.724%). Although the as-welded SZ exhibited excellent corrosion resistance, it became extremely vulnerable to intergranular cracking (IGC) and stress corrosion cracking (SCC) after sensitization. The large SCC susceptibility indices of the SZ samples ranged from 66.9% to 73.1%. These findings suggest that sensitization can strongly deteriorate the corrosion resistance of the Al-Mg FSW joint, which is of critical importance for the safety and reliability of marine applications.

The Effects of Titanium Dioxide (TiO2) Content on the Dry Sliding Behaviour of AA2024 Aluminium Composite

The low density, low expansion coefficient, and strong corrosion resistance at room temperature of Aluminium alloys have made them a popular choice for engineering applications. In this study, Aluminium AA2024 alloys are prepared with different weight contents of ceramic material, titanium oxide (TiO2) nanoparticles (0%, 2.5%, 5%, and 7.5% wt.) of a particle size of 30 nm using the metal stir casting method. The hardness property and wear resistance with the effect of heat treatment are investigated using a pin-on-disc wear device for both the base alloy and the reinforced alloys. The result shows the prosperity of 5wt.% of TiO2 to attain the optimum hardness and wear resistance. Using the optimum content of TiO2 and heat treatment, the hardness and wear resistance of 5wt.% TiO2-AA2024 nanocomposite has been significantly improved after heat treatment over the unreinforced Aluminium matrix. Statistically, the hardness and wear resistance are improved by 68% and 22%, respectively. This is due to an increased number of fine precipitates besides their uniformly distributed after heat treatment. Furthermore, casting AA2024 Aluminium alloy material mainly has S (Al2CuMg) and Al3TiCu phases. The appearance of a large number of S phases causes a significant improvement in the properties of the alloy.

Nanosecond laser processing and surface quality of SiC particle-reinforced AA2024 composite, homogeneous AA2024 aluminum alloy, and SiC: A comparative experimental study

This study performed comparative experiments on ablation behavior and surface quality obtained by nanosecond laser processing of silicon carbide (SiC) particle-reinforced 2024 aluminum alloy matrix composite (SiCp/AA2024), homogeneous SiC, and 2024 aluminum alloy. A nanosecond laser with a pulse fluence range of 0.68 ∼ 6.83 J/cm2 was used at irradiate samples of these materials, which were then ablated by various numbers of scanning passes (1 to 10) at a fluence of 6.83 J/cm2. The material melting could be achieved only for homogeneous AA2024. The ablation depth for SiC exceeded that of the composite, and the former could be ablated with a pulse fluence exceeding 3.42 J/cm2. The composite ablation threshold was higher than 4.10 J/cm2. Due to the thermal transition between the reinforcement and matrix, the melting threshold of the composite’s AA2024 matrix was lower than that of homogeneous AA2024 alloy. Moreover, the ablation threshold of SiC particles exceeded that of homogeneous SiC. The ablated surface roughness for the homogeneous material showed a sudden increase because of melting or oxidization, while that of the composite exhibited a gradual increase. For homogeneous SiC, oxidization accompanied by ablation and the accumulation of oxidization products on the surface deteriorated the laser pulse processing quality, especially in multipass scanning. In contrast, the dispersed distribution of SiC particles in the composite improved the composite’s machining feasibility.

Mechanical and metallurgical characterization of B4C and SiC reinforced stir casted AA6061 hybrid MMC

The present work was the novel investigation of mechanical and metallurgical characteristics of stir casted AA6061 based metal matrix composites (MMC) and hybrid MMCs. The reinforcements utilized in the investigation were silicon carbide and boron carbide. The thirteen stir casted MMC and hybrid MMC samples were tested for ultimate tensile strength, microhardness, fractography and wear performance. The stir casting process had enhanced the reinforcement distribution within the aluminium matrix. The enhancement in ultimate tensile strength was observed due to the addition of reinforcements in increasing weight percentages with the hybrid MMC exhibiting peak ultimate strength which was a 32.17% improvement against the non-reinforced AA6061 alloy. The formation of reinforcement particulates had enhanced microhardness of the specimens with the peak microhardness observed for boron carbide reinforced MMC exhibiting microhardness 25.41% higher than the base alloy. The hybrid MMC exhibited ductile fracture with highest elongation corresponding to the highest ultimate tensile strength. The wear performance analysis revealed reduced wear rates for the particulate reinforced specimen with highest weight percentage of reinforcements.

Finger millet husk ash Si3N4 as an alternative mold material for green sand mold casting of AA7075 alloys: an optimization study

Finger millet husk ash Si3N4 as an alternative mold material for green sand mold casting of AA7075 alloys: an optimization study

Insights into the Mechanical Properties and Correlation Between Strain Path and Crystallographic Texture of the AA2024 Alloy During Severe Plastic Deformation

Insights into the Mechanical Properties and Correlation Between Strain Path and Crystallographic Texture of the AA2024 Alloy During Severe Plastic Deformation

Peripheral coarse grain formation in AA2024 and AA6063 aluminium alloys- A comparative study

Multifaceted mechanical and physical characteristics such as light weighting, high strength to weight ratio, electrical conductivity, and ease of fabrication have helped aluminium alloys to find its application in aerospace and automobile sectors. The most famous aluminium alloy used in extrusion is AA 6063 because of its 100% extrudability. AA2024 is from the family of hard alloys which finds its applications in the strength requirements and major alloying additions comprise of Cu, Mg which contributes to age/precipitation hardening phenomena. Because of its inherent nature of high strength, it is challenging to extrude. Extrusion is one of the major metals forming processes which involve several process parameters such as, temperature, strain rate, ram speed and post forming heat treatment operations. To attain the specific mechanical properties, microstructure of the extrudate is of utmost importance and evolution of the same needs to be understood. Heat treatable aluminium alloys series of 2xxx, 6xxx or 7xxx are prone to peripheral coarse grain structure, which is responsible for the loss of mechanical and corrosion performance. To eliminate PCG entirely or to minimize it is the fundamental interest of extrusion industries and to come up with a workable solution, it is necessary to twig the microstructure evolution of AA6063 and AA2024 alloy during extrusion and after heat treatment. The present work is aimed at comparative study of the PCG formation of press quenched samples in AA6063 and heat-treated (T6) samples of AA2024.

Effect of ram speed on surface quality and mechanical properties during extrusion of AA2024 alloy

AA2024 aluminium alloys are extensively used for aerospace applications that demand higher strength requirements. However, the productivity during extrusion of AA2024 is highly limited and is about one tenth in comparison with soft alloys such as AA6063. In the present work, numerical simulation studies were carried out to extrude solid bar of AA2024 alloy under different processing conditions i.e billet preheat, ramspeed. For simulation studies, the limits of extrusion being selected are extrusion ratio and product exit temperature. From the studies, it was observed that higher preheat temperatures have resulted in higher product exit temperatures. Subsequently, press trial on 1400 Ton extrusion press was conducted to correlate with simulation results and extrudates were characterized to observe the effect of ram speed and extrusion load on surface quality. Increase in ram speed during extrusion has resulted in increase in mechanical properties. However, at a ram speed higher than 1.5 mm/s, surface cracks appeared on the sample and safe limiting ramspeed was 1.5 mm/s.

Optimization of process parameters for minimizing porosity level and maximizing hardness of AA2024 alloy coating on AZ31B alloy using computational response surface methodology

Optimization of process parameters for minimizing porosity level and maximizing hardness of AA2024 alloy coating on AZ31B alloy using computational response surface methodology

MICROSTRUCTURAL ANALYSIS AND MECHANICAL PROPERTIES OF THREE-LAYERED STACK OF FSAM AA7075-CU ALLOYS

Friction Stir Additive Manufacturing (FSAM) is a novel solid-state technique which is performed on the basis of Friction Stir Welding (FSW) process. Compared with conventional fusion welding, FSW overcomes welding defects when it is used for joining dissimilar metals. In this study, Friction Stir Additive Manufactured AA7075-Cu alloy is performed on the principle of FSW by which the materials are not melted during the process. The FSW process is performed on the three-layered stack of alloy combinations of AA7075-Cu alloys. The input process parameters, such as axial load, welding feed and rotational speed at different levels, are considered. The effect of mechanical properties, such as microhardness, Ultimate Tensile Strength (UTS) and % elongation, is observed. The microstructure on the welded nugget zone is obtained using Scanning Electron Microscope (SEM). The microhardness of FSAM AA7075-Cu alloys is significantly increased when compared to the microhardness of AA7075 and Cu alloys. The crystalline structure on the welded nugget zone is observed on the microstructure of FSAM AA7075-Cu alloys from SEM microstructures of parent zone as well as welded zone.

AA6063 and AA6951 Aluminum Alloy Billet Casting Parameter and Heat Treatment Optimization

In this study; The properties of billets of 3 different diameters of AA6063 and AA6951 aluminum alloys were investigated by trying different methods. In line with this study, the properties of the alloys were investigated by comparing the casting and homogenization parameters of alloys of different sizes. The metallographic and mechanical analyzes of the samples were made and presented in the tables. Casting and homogenization parameters providing the most suitable parameter were determined according to the values.

Comparative study of microstructural and mechanical properties of robotic CMT and GMAW welded 7475-T7351 aluminium alloy joints

The objective of the present investigation is to characterize the mechanical and microstructural behaviours of CMT welded AA7475 alloy in T7351 temper conditions and compare it with the GMAW welding process. The TS, YS, elongation, and hardness values are measured for both CMT and GMAW weld. It is observed that the CMT welded sample has better mechanical properties as compared to GMAW. Typical metallographic images of CMT and GMAW samples were analysed for the AA7475-T7351 joint. The dispersion of precipitates throughout the weld was assessed using EDX. In order to completely describe the failure patterns of the welded joint for both CMT and GMAW, SEM was used to analyse the fractography of WM of the fractured tensile samples. Weld metal (WM), base metal (BM), as well as the generation of the secondary phase in the heat-affected zone (HAZ), were all evaluated using EDX and SEM micrographs.

Discrepancy in ductility improvement in repeated stress relaxation of AA7075

The stress relaxation test is a commonly used transient test to determine the deformation kinetics during plastic deformation. This study reports the time-dependent deformation behavior of AA7075 alloy under different temper conditions. The deformation parameters, such as the apparent and true activation volume were estimated using single and repeated stress relaxation tests respectively. The results indicate that dislocation–dislocation interaction plays a critical role in the deformation behavior of the solution-treated condition, whereas dislocation–precipitate interaction dominates in the aged specimens. Additionally, the study found that single stress relaxation enhances the ductility of the deforming specimen, regardless of the temper condition. The ductility during repeated relaxation however had negative effects in aged samples. The possible mechanisms responsible for this discrepancy are discussed, providing a comprehensive overview of the time-dependent deformation behavior of AA7075 alloy.

Intergranular corrosion and mechanical property evolution in AA2024 alloy through heat treatment

Intergranular corrosion and mechanical property evolution in AA2024 alloy through heat treatment

The Role of Friction Stir Processing Parameters and Hybrid ZrC/WC Reinforcement Particles in Improving the Surface Composite Dissimilar Matrix’s Dynamic Behavior and Microstructure Refinement

This study examined the impact of hybrid reinforcement particles, specifically zirconium carbide (ZrC) and tungsten carbide (WC), as well as the parameters of friction stir processing (FSP), on the microstructure, mechanical properties, and dynamic behavior of aluminum alloys. The hybrid particles were integrated into the aluminum alloy using friction stir processing (FSP). The fabricated metal matrix composites (MMCs) were characterized using optical microscopy, scanning electron microscopy (SEM), and dynamic mechanical analysis (DMA). The results showed that the FSP parameters and reinforcement particles played an important role in improving the grain refinement of the MMCs. This study’s results suggest that the FSP samples’ UTS can be maximized using a tool rotation speed of 600 rpm and a traverse speed of 30 mm/min. The grain refinement in the composite surface was attributed to the dynamic recrystallization during the friction stir processing (FSP) process. The reinforcement particles also acted as grain growth restrictors, further refining the grain size. This resulted in a 34% increase in ultimate tensile strength compared to AA2024 alloys and a 12% increase compared to AA7075 alloys. The composite surface also exhibited enhanced dynamic properties, with an increase in impact energy of 26%. The free vibration test showed that the hybrid reinforcement particles significantly improved the strength and damping capacity of the aluminum alloys, resulting in a high resonant frequency. This is important for applications such as vibration damping and noise reduction.

Microstructure and mechanical properties in additive manufacturing by friction surfacing of AA6061 alloy

This present study uses a novel solid-state additive manufacturing method based on friction surfacing as a mechanism for layer-upon-layer deposition. This utilizes severe plastic deformation to create a homogeneous fine-grain microstructure without melting to avoid solidification-related defects. The deposition of AA6061-T6 aluminum alloy was achieved by rotating a 20 mm diameter rod on top of a substrate at 1000 RPM and applying a 300 mm/min transverse speed with an axial feed rate of 50 mm/min. Advanced macro/microstructural techniques characterized the grain and precipitate structures in the deposited material, i.e., electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM) analyses, along with micro-hardness and tensile testing of the mechanical properties. The multi-layer deposition contains a refined grain size in the range of 5–10 μm and sub-grains less than micron size, while a reasonable reduction in mechanical properties compared to the as-received rod was observed; in which hardness was reduced from 114 HV to 49 HV, and the tensile strength was reduced from 333 MPa to 161 MPa. These reductions are largely attributed to the dissolution of precipitates in the original rod due to the high temperatures imposed by friction and deformation. Achieving metallurgical bonding between the layers while suppressing porosity is critical to additive manufacturing, and this feasibility study of friction surfacing demonstrates this can be achieved along with superior isotropic mechanical properties. Based on the results, it was observed that additive manufacturing by friction surfacing is particularly suitable for metals that are sensitive to heat during deposition, though parameter optimization and secondary treatment may be required to enhance properties further.

The effect of trace level copper content on intergranular corrosion of extruded AA6082-T6 alloys

The effect of trace level Cu content on intergranular corrosion in an acidified salt solution has been systematically studied in four AA6082-T6 extrusions containing 0.001, 0.02, 0.03 and 0.05 wt% Cu. Although these Cu concentrations are smaller than those expected to directly contribute to intergranular corrosion (IGC) in aged AA6082 alloys, IGC is observed in the present experiment even in alloy with the lowest Cu content. Whereas the extent of IGC is negligibly small in the alloy containing 0.001 wt% Cu, it increases with increasing Cu content. Profound IGC is observed in the alloy containing 0.05 wt% Cu. Microstructural characterization reveals Cu segregations along some grain boundaries in each alloy. The different alloys demonstrate differences in the size and number density of precipitates as well as in the width of precipitate free zones.

Tensile, microhardness and microstructural characteristics of friction stir welded/processed AA7075 alloy: A review

The aircraftand automobile industries have a great demand for aluminium alloys such as AA7075 due to their excellent features. However, it is difficult to join AA7075 using electric arc welding process. Therefore, a novel green welding process namely, friction stir welding (FSW), could be employed for fabricating the joints without any defects. FSW, is a proven solid state joining process capable to join several key engineering materials such as aluminium, magnesium, copper, titanium, and several steel grades. In this review study, the FSW characteristics of a well-known aircraft alloy AA7075 is presented systematically. Weld/processed characteristics such as microhardness, ultimate tensile strength, and microstructural are discussed. It is observed that, FSW process could yield better joints without any defects unlike in traditional welding processes. By proper selection of tool and process parameters will result in improvement of weld efficiency of AA7075 alloy. Fine grained microstructure resulting in better hardness and strength of AA7075 joints. However, there is lack of studies that needs to be carried out on integration of the digital tools such as artificial intelligence (AI) and machine learning (ML) is necessary to reduce FSW time.

Study of Backpressure on the Composition and Characteristics of the AA5083 Alloy During ECAPed

Equal Channel Angular Processing Process at room temperature along varying backpressure level and numbers of passes produced hefty billets of 25 mm×25 mm×100 mm industrial alloy AA5083 with an ultrafinegrained microstructure. Supersaturated solid iron in an aluminium matrix was treated in brittle cast AA5083 during Equal Channel Angular Processing with Sixteen passes and a 285 MPa backpressure. The Equal Channel Angular Processing alloy’s strength, ductility, and microhardness were all greatly improved. Increased backpressure improves ductility of Equal Channel Angular Processing alloys, the workability and delays the craking of intermetallic particles. Alloys treated by Equal Channel Angular Processing have improved workability due to backpressure. The AA5083 alloy’s strength and microhardness were greatly improved. When an initially coarse-grained alloy undergoes 3 passes of Equal Channel Angular Processing with a 220 MPa backpressure, its microhardness and room strength (185 HV, UTS = 327 MPa) are significantly higher than their typical values following conventional processing with cold rolling or hot pressing. In Equal Channel Angular Processing, a super saturated solution was generated with a peak soluble of 0.6 wt.% of iron allow the ageing of the usually non-hardenable metal. The cast alloy treated using the Multi-pass approach has positively impacted toughness, elasticity, and microhardness.

Effect of nano-TiO2 particles addition on dissimilar AA2024 and AA2014 based composite developed by friction stir process technique

Aluminum composite materials have gained immense popularity in the construction and aerospace industries as these materials are lightweight, durable, and exhibit a high strength-to-weight ratio. The present study aims to develop dissimilar AA2024 and AA2014-based composite materials using nano-TiO2 reinforcement particles via Friction Stir Processing (FSP) techniques. The FSP technique is a solid-state processing method that is used to modify the properties of metal alloys without altering their chemical composition. The samples were prepared by placing a nano-TiO2over AA2024 and AA2014 aluminum alloys sheet and subjected to FSP process parameters. The microstructure, hardness, and tensile properties of the composite samples were assessed using scanning electron microscopy (SEM), Vickers hardness tester, and tensile testing machine respectively. The results showed that the FSP technique led to the formation of a homogeneous and fine-grained microstructure in the composite samples. The nano-TiO2 reinforcement also provided additional strengthening to the AA2024 and AA2014 aluminum alloys matrix resulting in improved hardness and tensile properties of the composites. The resulting composites exhibited enhanced wear resistance properties. The FSP method presented in this study has implications for extending the properties of other metal alloys, opening up new avenues for research in the field of materials science.